1. Field of the Invention
The invention relates to a control system, and more particularly to a control system of a milling machine.
2. Description of the Related Art
Referring to FIG. 1, a milling machine 1 disclosed in R.O.C. Patent Publication Number 479585 includes a column 11, an overarm 12 and a clamp 13 movably mounted to the column 11, a spindle 15 extending rotatably through the overarm 12 and mounted with a cutter 14, a ball screw 16 extending pivotably through the column 11, and a motor 17 mounted on the column 11 for driving the rotation of the ball screw 16. The clamp 13 is adapted for clamping a work piece (not shown in the Figure). The ball screw 16 includes a first threaded section 161 and a second threaded section 162 that extend threadedly through the overarm 12 and the clamp 13, respectively, and that have opposite threading directions.
When the motor 17 drives the ball screw 16, the overarm 12 and the clamp 13 move toward or away from each other. However, movement of the cutter 14 may be restricted, which may make some machining tasks more difficult or more time consuming to accomplish.